Method of providing display on molded base

ABSTRACT

A molded base, for example, a cabinet of a radio receiver, is molded with a synthetic resin and at least one display element made of, for example, a metal, is embedded in the molded base so as to expose one surface of the element. The surface of the display element is then covered with a finish coating to form a substantially uniformly coated layer. The coating on the surface portion of the embedded display element and further at least a portion of the surface of the display element is subjected to mechanical treatment so that the material surface portion is exposed on the display element, whereby the molded base is provided with an aesthetic and decorative display thereon.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for providing a display on amolded base and, more particularly, to a method of providing a displayon a molded base having an aesthetic and decorative design on a moldedbase by embedding a display element such as a plate or frame or anyother similar member in the molded base and forming a finish coatingover the surface portion of the embedded display element and exposing aportion of the surface of the display element.

2. Description of the Prior Art

Devices, instruments, apparatus of the like such as electronic devices,e.g., radio receivers, carry names of manufacturers, trade marks, namesof items or the like on their cabinets. One of the simplest methods toprovide a display on the cabinet of a device, or the like, or form apattern display for decorative purposes thereon, is to subject thecabinet, for example, of synthetic resin to a silk screen printingprocess. This method, however, does not provide a display of highquality and durability because it is difficult to produce a decorativeand aesthetic appearance on the display and such a display tends to beremoved or come off with time, due to abrasion. In order to give ametallic appearance to a display on the cabinet of a device or the like,it has been proposed that a decorative aluminum plate with the name of amanufacturer, a trade mark or the like is allowed to adhere to a surfaceof the surface-finished cabinet of synthetic resin. This methodapparently requires the use of an adhesive and consequently a step ofcoating the adhesive on the decorative aluminum plate. This method alsorequires time for drying the coated adhesive before the resultingcabinet is transferred to a step which follows so that it takes a longertime than a step in which no adhesive is employed. The use of theadhesive also offers a risk that the coated adhesive will be pressed outbetween the connecting portion and consequently the resulting appearanceis impaired. The decorative plate so attached to the cabinet may in somecases present a disadvantage in that it might come off of the cabinetwith time, due to aging.

SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to provide a method forproviding a decorative and aesthetic display on a cabinet of syntheticresin, which can remove or improve the defects and disadvantagesconventional methods present.

Another object of the present invention is to provide a method forproviding a decorative and aesthetic display on the cabinet of a device,instrument, apparatus or the like which does not require a step ofcoating an adhesive on the surface-finished cabinet thereof.

A further object of the present invention is to provide a method forproviding a decorative and aesthetic display on the molded base of thecabinet therefor which does not provide a risk that the surface of thecabinet thereof is stained or impaired in appearance.

A still further object of the present invention is to provide a methodfor providing a decorative and aesthetic display which can allow thedisplay portion to be attached or secured to the cabinet surface in sucha manner that it cannot be readily removed or come off.

A still further object of the present invention is to provide a methodfor providing a decorative and aesthetic display which can be secured orattached to the cabinet surface with high precision and accuracy.

According to one aspect of the present invention, there is provided amethod of forming a display on the molded base which comprises the stepsof molding a synthetic resin into a base with a display element embeddedin the synthetic resin so as to expose a portion of the surface of theembedded display element; covering the exposed surface portion of thedisplay element with a finish coating together with the surface of thesynthetic resin base; and subjecting the coating on the surface portionof the embedded display element to mechanical treatment so as to exposethe surface portion thereof.

The above and other objects, features and advantages of the presentinvention will become apparent during the course of the followingdetailed description of an illustrative embodiment which is to be readin connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating a radio receiver having afront base panel which is prepared by the method in accordance with thepresent invention.

FIG. 2 is a cross-sectional view illustrating a female mold forming thefront base panel to be used for the method in accordance with thepresent invention and taken along a line corresponding to the line A-A'of FIG. 1.

FIG. 3 is a cross-sectional view illustrating a female mol and a malemold forming the front base panel of the radio receiver as shown in FIG.1 and taken along the line corresponding to the line A-A' of FIG. 1.

FIG. 4 is a cross-sectional view illustrating the female mold and themale mold shown in FIG. 3, and taken along a line corresponding to theline B-B' of FIG. 1.

FIG. 5 is a perspective view illustrating a decorative metal elementwith the form of a plate and another display element in the form of aframe to be embedded in the front base panel.

FIG. 6 is a perspective front view illustrating the front base panel ofthe radio receiver of FIG. 1 obtained by the method in accordance withthe present invention.

FIG. 7 is a perspective back view illustrating the front base panel ofFIG. 6.

FIGS. 8 and 10, respectively, are cross-sectional views illustrating theportion of the front base panel, where the display element in the formof a plate is embedded, taken along the line C-C' of FIG. 7 incombination with the steps of the method in accordance with the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, there is shown a radio receiver 1 having a cabinet2 composed of a front base panel 3, which is manufactured in accordancewith the method of the present invention, and a rear base panel 4. Asbest shown in FIGS. 6 and 7, the front base panel 3 includes a frontpanel portion 3a, a right side panel portion 3b and a left side panelportion 3c. The rear base panel 4 includes a rear panel portion (notshown), an upper side panel portion 4a, and a lower side panel portion(not shown). The numeral 5 shows a tuning scale plate. The front panelportion 3a has a speaker grille 6 composed of a wire net for protectinga speaker (not shown) to be fitted thereto. An operating knob 7 is alsoprovided through a hole 7a of the front panel portion 3a. The numeral 8is a display element in the form of a plate, as shown in FIG. 5, havinga display portion such as letters, figures or designs for representationor decoration; in this case, capital letters "IC RADIO", representingthe item of goods are provided on the display element. It is, of course,to be noted that any variation and modification in the display portioncan be made according to the purpose of the display element 8. Forexample, the numeral 9 is another type of the display element which maybe in the form of a square U-shaped frame and which is used mainly foradorning the cabinet 2. A dial knob 10a is mounted on the upper sidepanel portion 4a of the rear base panel 4 and arranged so as to transferthe needle of the tuning scale plate 5 and operate a variable condenserdisposed in the cabinet 2 to tune a desired receiving frequency. On theupper side panel portion 4a of the rear base panel 4, there is alsoprovided a volume control knob 10b with a power transfer switch forturning on and off the power transfer and controlling the volume. Thenumeral 10c is a rod antenna mounted on the upper side panel portion 4a.

The method in accordance with the present invention can impart anaesthetic, decorative or metallic appearance of a display element on thesurface of the front base panel 3 of the cabinet 2. The method involvesthe appearance of surface portions of the display elements 8 and 9 andany other display element in any appropriate form and of materialdifferent from the material of the front base panel 3. For example, whena metal is used as a material for the display element 8 or 9, thismethod can give a metallic appearance on the surface portion of thedisplay element in good contrast to the appearance of the front basepanel 3 itself.

Turning now to FIG. 2, a female mold 11 has a cavity 11a for forming thefront base panel 3 of the radio receiver 1 by means of the method inaccordance with the present invention. The female mold 11 is provided atthe inner surface of its cavity 11 with concave portions 13 to securedlyreceive the display element 8. The concave portions 13 should besubstantially equal in size to the display portions 8a or projectedportions of the display element 8 although the shape of the concaveportions 13 is in such a reverse relationship with the projectedportions 8a as to secure and fit the projected portions 8a of thedisplay element 8. The concave portions 13 may be formed on the surfaceof the inner cavity 11a of the female mold 11 by means of electricaldischarge machining process. The electrical discharge machining processmay be carried out using, for example, a copper cathode (not shown)having substantially the same shape and size as the projected portionsor display portions 8a of the display element 8 to be copied on thesurface of the inner cavity 11a of the female mold 11. This method canallow the accurate and precise copying of the projected portions 8a ofthe copper cathode at a predetermined portion on the surface of theinner cavity 11a in a reverse relationship. Similarly, a concave portion14 for receiving the display element 9 in the form of, for example, asquare U-shaped frame may be formed on the surface of the inner cavity11a of the female mold 11.

Referring to FIG. 5, the display element 8 has display portions 8a inthe form of projections on the plate. And the display element 9 has adisplay portion 9a in a square U-shaped form. It is to be noted,however, that shapes of the display portions of the display elements 8and 9 or display portions of any other display element which may bedisposed arbitrarily according to a desired appearance of the cabinet ofa device or the like are not limited to particular ones and they may bein any appropriate shape and size. Materials for the display elements 8and 9 and any other display element may include, for example, a metalsuch as aluminum, nickel or brass or any other suitable material andthey may be different from each other while they should be differentfrom the material and/or the color of the front base panel 3. Thematerial may be chosen for the display element 8 or 9 according to adesired appearance on the front base panel 3 of the cabinet 2. Referringfurther to FIG. 5, the display element 9 includes a bottom frame portion9b, a right side frame portion 9c, and a left side frame portion 9d. Thebottom frame portion 9b has a thickness t thinner than the thickness ofthe front panel portion 3a of the front base panel 3 and the right andleft side frame portions 9c and 9d have each a thickness T thicker thanthe thickness thereof. A crossbeam 9e is also disposed at the lower rearportions of the side frame portions 9c and 9d and provided with a holeor holes 9f for mounting parts of a device to be fitted in the cabinet2.

Referring to FIGS. 3 and 4, the display or projected portions 8a of thedisplay element 8 are inserted into and fitted to the concave portionsor cavities 13 of the inner cavity 11a of the female mold 11. Likewise,the front display portions 9a in the square U-shaped form is fitted tothe corresponding concave portion or cavity 14 thereof. In this case,the display elements are not required to have their surfaces finished orcleaned before attachment thereof to the female mold 11. In order tokeep the display elements 8 and 9 from being withdrawn or removed fromthe respective concave portions 13 and 14 during the molding step ofmolding the front base panel 3, vacuum suction may be effected through ahole or holes 11b provided in the female mold 11 in such a manner thatthe hole or holes are arranged so as to communicate the exit or exits tothe inner surfaces of the concave portions or cavities 13 and 14.

Referring further to FIGS. 3 and 4, a male mold 12 is then inserted intothe cavity 11a of the female mold 11 and positioned at an appropriateposition so as to provide a predetermined space 15 which defines thethickness of the wall of the front base panel 3. As best shown in FIG.4, a transferrable mold 16 is also placed or located between the innerportion of the crossbeam 9e of the display element 9 and the imaginaryback surface portion of the molded front panel portion 3a to define theback surface portion of the front panel portion 3a and prevent a moltenmaterial charged into the space 15 from being introduced into the spaceportion as defined therebetween. The transferrable mold 16 may bewithdrawn from the interposed position in a direction vertical to theplane of the drawing after the charged material is cured to form thefront base panel 3. As shown in FIG. 3, the male mold 12 may be providedwith a projection 12a so as to define a hole or holes for mounting apart or parts of the device, e.g., radio receiver 1. The projection 12ais arranged so as to have a shape and size corresponding to the hole orholes to be disposed of in the front base panel 3. The projection 12a isalso arranged such that its surface is brought into contact with thesurface of the inner cavity 11a of the female mold 11 in such a manneras not to have the charged molten material fed into the portion definedby the surfaces of the male and female molds 11 and 12. The projection12a may be formed integrally to or separately from the male mold 12. Inthe above-mentioned manner, there are formed the hole 5a for the tuningscale plate 5, the hole 6a for the speaker grille 6, the hole 7a for theoperating knob 7 and any other hole necessary for mounting parts to beaccommodated in the cabinet 2.

After a preparatory procedure is set by registering the male mold 12into the female mold 11 with the other arrangement ready, a moltenmaterial 17 is then introduced or charged into the space 15 definedbetween the male mold 12 and the female mold 11 so as to form the frontbase panel 3. The molten material charged thereinto is then allowed tocool to room temperaure to cure the molten material. The molded frontbase panel 3 is withdrawn by releasing the male mold 12 from the femalemold 11 after the molten material 17 solidified.

Turning now to FIG. 8 with reference to FIG. 7, the molten material 17is introduced or charged into the space 15 defined so as to formextensions 19 to cover at least a portion or peripheral portions, as inthis case, of the rear of the display element 8 with the oppositesurface of the display element 8 exposed. As the extensions 19 areformed integrally with the rear surface of the front base panel 3, thedisplay element is attached securedly to the front base panel 3 withcausing no or less risk that it is removed or taken away even if apressure or force would be applied backwards from the front side of thefront base panel 3. On the other hand, as shown in FIG. 8, the displayelement 9 in the square U-shaped frame form mainly for adornment isembedded in the molten material so as not to expose its rear surface tothe back surface of the front base panel 3. Thus, the display portions8a of the display element 8 in the plate form and at least a portion ofthe display portion 9a of the display element 9 in the frame form areformed so as to project from the surface plane of the front base panel3. Any other display element may be mounted in substantially the samemanner as hereinabove mentioned.

Referring to FIG. 9, the molded base panel 3, as prepared hereinabove,is then coated with a finish coating 18 in known manner as by sprayingor brushing a material for finish coating or by immersing the moldedbase panel 3 in the finish coating bath to form a substantially uniformcoating 18 having a thickness preferably from about 0.1 to 0.8 mm. Apaint for the finish coating is not restricted to any particular one andmay include, for example, a mixture of an acrylic resin or a urethanetype resin with a lacquer. As the finish coating 18 is formed as a soleor single coating, no difference in color can be seen on the jointbetween the display elements 8 and 9 and the frong base panel 3. Thefinish coating 18 can function as rendering invisible any physicalsurface defects such a burrs, scars or wrinkles formed on the surface ofthe base panel during the molding or during the solidifying of themolded base panel after drying due to irregularities on temperatures. Itcan also color the cabinet 2 in a desired manner and render the value ofgoods higher.

Referring now to FIG. 10, the front base panel 3 with the finish coating18 formed thereon is then subjected to a finish surface treatment inorder to expose the display portions 8a and 9a of the respective displayelements 8 and 9. For this purpose, for example, milling may be effectedto remove the coating 18 over the display portions 8a and 9a. Themilling may be conducted by rotating the teethed tool 20 of a millingmachine in the arrow direction as illustrated as the symbol "X", whiletransferring a table with the base panel 3 thereon in the arrowdirection as illustrated as the symbol "Y", whereby the finish coating18 over the display portions 8a and 9a is removed and further a portionof the surfaces of the display portions 8a and 9a is cut away andpolished to provide a finished surface. The finish surface treatmentwith a grindstone or grinding wheel may be carried out by cutting inplace of milling. The surface treatment can give an aesthetic,decorative or metallic appearance of the display elements 8 and 9. Thesurface treatment may be carried out in such a manner that, for example,scars by the teeth of the milling tool 20 are intentionally remained onthe surfaces of the display portion 8a or 9a, thereby imparting anotheraesthetic and decorative appearance in order to satisfy diversifiedneeds.

In accordance with the present invention, it is to be noted that,although the description is made heretofore mainly on the displayelements 8 and 9, the number, shape and size of the display element tobe provided in the front base panel 3 are not restricted to particularones and may be chosen according to purposes and usages of the device orthe like. If needed, the back base panel 4 may be prepared and treatedin substantially the same manner as the front base panel 3. It is alsoto be noted, although needless to say, that, as hereinabove mentioned,the number, shape, type, size and the like of the display portion of thedisplay element are not restricted to particular ones, too, and may beselected, depending upon purposes and usages of the display elementalthough the description made hereinabove is directed mainly to thedisplay portion 8a carrying capital letters "IC RADIO" representing thename of the device and the display portion 9a in the frame form. It canalso be noted that a plurality of display elements as in this case areprovided and the display elements used are of material different fromeach other, thereby giving a differently aesthetic and decorativeappearance on the cabinet of the device. For example, when the displayelement 8 is composed of aluminum and the display element 9 is of brass,the front base panel 3 can impart a silver-like appearance on thedisplay portion 8a of the display element 8 in good contrast to acombination with a golden-like appearance on the display portion 9a ofthe display element 9. It is further to be noted that a display elementor elements such as the display element 9 in the frame form may beprovided for the purpose of strengthening the front base panel 3 as wellas for the purpoe of adorning the cabinet 2.

It is further to be noted that the crossbeam 9e of the display element 9in the frame form is provided with holes 9f through which a part orparts of relatively heavy-weight such as a power transformer or aprinted circuit board having circuit parts attached thereto may beconnected to the cabinet 2. This allows the heavy weight not to beapplied directly to the cabinet 2, thereby preventing the cabinet frombeing damaged or destroyed.

The front base panel 3 is then assembled with the back base panel 4 togive the cabinet 2 for the radio receiver 1 as shown in FIG. 1. Thiscabinet 2 possesses the display portions 8a and 9a glittering inmetallic color in good and pronounced contrast to the other surface areaof the front panel portion 3a in color different from the color orcolors of the display portions 8a and 9a.

The cabinet 2 as hereinabove mentioned is particularly applicable to theradio receiver, but it should be noted that the present invention is notrestricted to cabinets for radio receivers and may be applicable to acabinet for any other device, instrument or apparatus.

I claim as my invention:
 1. A method of forming a base panel for acabinet for an electrical device comprising the steps of providing afemale mold with a female cavity formed with depressions for receivingone or more display elements of a first material with at least one ofsaid display elements formed with a cross bar, placing said one or moredisplay elements in said depressions, inserting a male mold into saidfemale cavity of said female die, filling a space between said male andfemale dies with molten synthetic resin material embedding said one ormore display elements, removing said base panel from said male andfemale molds, covering exposed surfaces of said base panel includingsaid display elements with a coating of finish material, andmechanically removing said finish coating from exposed surfaces of saiddisplay elements.
 2. The method according to claim 1, wherein said basepanel is embedded with at least two display elements of materialsdifferent in color from each other and portions of the surfaces of saiddisplay elements are treated by removing the coating thereon so as toexpose the surface portions of said display elements having differentcolor tones.
 3. The method according to claim 1, wherein said syntheticresin base is provided with at least one display element which is adecorative display element in the form of a frame with its surfaceportion exposed from the base surface and the display element isdisposed so as to reenforce the strength of the base.
 4. The methodaccording to claim 1, wherein at least one of said display elements iscovered at its rear portion with an extension integrally andcontinuously formed in the synthetic resin base and the extension isdisposed so as to allow the attachment of said display element to thebase.
 5. The method according to claim 1, wherein at least one of saiddisplay elements is provided with at least one projection representing aletter, figure or design.
 6. The method according to claim 1, whereinsaid synthetic resin base forms a part of a cabinet.
 7. The methodaccording to claim 6, wherein at least one of said display elements isprovided with means for mounting a part to be accommodated in thecabinet.